Queue.h

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#ifndef SCHEDULER_QUEUE_H
#define SCHEDULER_QUEUE_H

template <class T, uint8_t NMEMB>
class Queue {
  static_assert(NMEMB && !(NMEMB & (NMEMB - 1)), "Queue::NMEMB should be power of 2");
public:
  Queue() :
    m_put(0),
    m_get(0)
  {}

  unsigned int available() const
    __attribute__((always_inline))
  {
    return ((NMEMB + m_put - m_get) & MASK);
  }

  unsigned int room() const
    __attribute__((always_inline))
  {
    return ((NMEMB - m_put + m_get - 1) & MASK);
  }

  void push(const T* data)
  {
    await(room());
    unsigned int next = (m_put + 1) & MASK;
    m_buffer[next] = *data;
    m_put = next;
  }

  void push_P(const T* data)
  {
    await(room());
    unsigned int next = (m_put + 1) & MASK;
    memcpy_P(&m_buffer[next], data, sizeof(T));
    m_put = next;
  }

  void pull(T* data)
  {
    await(available());
    unsigned int next = (m_get + 1) & MASK;
    m_get = next;
    *data = m_buffer[next];
  }

private:
  static const unsigned int MASK = (NMEMB - 1);
  volatile unsigned int m_put;
  volatile unsigned int m_get;
  T m_buffer[NMEMB];
};

#endif